Transistor elemekt and transistor circuit

ABSTRACT

A UNIVERSAL TRANSISTOR ELEMENT CAPABLE OF MANY APPLICCATIONS. THE ELEMENT INCLUDES WITHIN A SEMICONDUCTOR BODY AT LEAST FIRST AND SECOND SPACED ZONES SPACED FROM A THIRD ZONE, AND ONE OR TWO BASE ELECTRODE CONNECTIONS TO THE BODY MATERIAL. THE SPACING OF THE FIRST AND SECOND ZONES TO THE THIRD ZONE IS SMALLER THAN A DIFFUSION LENGTH ENABLING TRANSISTOR ACTION TO TAKE PLACE BETWEEN EACH OF THE FIRST AND SECOND AND THIRD ZONES, BUT THE SPACING BETWEEN THE FIRST AND SECOND ZONES IS GREATER THAN A DIFFUSION LENGTH PREVENTING DIRECT TRANSISTOR ACTION. WITH TWO BASE ELECTRODES, THE APPLICATION OF A VOLTAGE THEREACROSS ENABLES CONTROL TO BE EXERCISED OVER THE INTERNAL TRANSISTOR ACTION.

March 30, 1971 J M. CLUWEN TRANSISTOR ELEMENT AND TRANSISTOR CIRCUIT Original Find Doc. 1. 1953 United States Patent Oflice Re. 27,110 Reissued Mar. 30, 1971 27,] I0 TRANSISTOR ELl-lMl-lt "I AND TRANSISTOR (.IRCUI'I' Johannes Meyer Cluwen, Emmuslngel, Eindhoven, Netherlands, asslgnor to US. Philips Corporation, New York,

Original No. 3,299,281, dated Jun. 17. 1967, Ser. No. 395,550, Dec. 1, 1953. Application for reissue Sept. 3. 1968, Ser. No. 760,391

Claims priority, application 2heltherlands, Dec. 1, 1952,

Int. Cl. H01] 13700; H03k 5/20 US. Cl. 307-303 22 Claims Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

two base electrodes, the application of a voltage thcrcacross enables control to he arcrciscd over the internal transistor action.

The invention relates to a transistor element made of a semi-conductive mass of one conductivity type comprising zonesof the other conductivity type. this mass and at least a few of the zones being provided with connecting electrodes. and to a circuit comprising such a transistor element, the invention having for its object to provide a universal transistor-element with many possibilities of connection due to a particular realisation of the transistor element.

In accordance with the invention, at least two zones, provided with connection electrodes. are arranged each at a distance from a third zone provided or not provided with a connecting terminal, which distance is smaller than the characteristic diffusion length of the minority carriers in the mass, the relative distance between the first zone and the second zone exceeding this characteristic diffusion length.

In order the invention may be readily carried into effect, it will now he described with reference to the accompanying drawing.

FIG. 1 shows a transistor element according to the invention.

FIG. 2 shows a circuit arrangement comprising such an element for amplifying an electric signal.

FIGS. 3 and 4 show two variants of the element shown in FIG. 1.

FIG. 5 shows a variant of the circuit shown in FIG. 2.

FIG. 6 shows a gating circuit comprising a transistor element according to the invention.

FIG. 7 shows a similar amplitude-detector circuit.

FIG. 8 shows a variant of the circuit shown in FIG. 7.

FIG. 9 shows a frequcncy-dcmodulator circuit comprising a transistor element according to the invention.

FIG. 1 shows a transistor element according to the invention comprising a comparatively highrcsislivity. scmiconductive mass it of one conductivity type (n). in which comparatively [high] low-resistivity zones 1, 2 and 3 of the other or opposite conductivity typc (p) are preferably provided. Such zones may, for example, be obtained by causing a suitable material to diffuse at a definite temperature and for a definite time into the mass n. The transistor element is provided with connecting electrodes 0 and c. connected to the p-zoncs 1 and 2 and adapted to serve as the emitter electrode and the collector electrode respectively. and the connecting electrodes b and h of which at least one operates as a base electrode, while the third p-zonc 3 is provided with a connecting electrode e.

The operation of the transistor is, as is known, based on the following principle. In a p-zonc, the majority carriers are holes, and in an n-zone, electrons. However, in the case of a pm junction biased in the forward direction holes in the n-zone, and also electrons in the pzone, will diffuse over a definite distance, termed the characteristic diffusion length, before recombining and disappearing, these holes forming. it is true, the minority carriers in this n-zone. but permitting the current to pass to an n-p junction following the n-zone and biased in its blocking direction. if the thickness of the n-zone is smaller than this characteristic diffusion length.

The distance between the zones 1-3 and 23 is smaller than the characteristic diffusion length of the minority carriers in the mass it so that the portions 1-n-3 and 2-n-3 respectively of the transistor element, provided with the connecting electrodes eb e' and ch e respectively, may be connected each as a transistor amplifier. The relative distance between the zones 1 and 2, however. exceeds this characteristic diffusion length, so that a direct transistor action between the portions 1n-2 of the transistor element is avoided.

A transistor element as shown in FIG. 1 may be used with advantage in the amplifying circuit shown in FIG. 2. The input signal V to be amplified is supplied to the emitter electrode e and the base electrode b is connected to earth or ground. The electrode e is floating and could, if desired, be omitted. The electrode b is connected to earth through a voltage source 5, having a low internal resistance at least for the high signal frequencies and a. voltage of a few volts only, while the collector electrode c is connected to earth through a comparatively high output impedance 6 and a supply voltage source 7.

The circuit operates as follows: Owing to the voltage source S. the p-n junction between the zone 1 and the mass 11 is operated in the forward direction. The same applies to the p--n transition between the zone 3 and the mass it in the proximity of the zone 2. Thus signal current flows from the voltage source V through the emitter electrode e, the zone 1, the mass n, the zone 3, the mass n. the zone 2 and the collector electrode c to the output impedance 6, a voltage amplification being thus obtained. since the input impedance for the signal source V is lower than the impedance 6. At the same time a capacitative reaction of the output voltage through the impedance 6 and internal transistor capacities on the signal source V and hence a decrease in limit frequency for the operation of the transistor is avoided,

since the zone 3 is at a substantially constant potential (Le. slightly less negative than the electrode b with respect to earth), so that the internal transistor capacity between the zone 3 and the mass n has substantially no detrimental effect in the proximity of the zone 1.

In order to limit the direct current flowing through the mass n from the electrode b, to the electrode b :1 mass 11 having an increased specific resistivity compared with conventional transistors may be used. The disadvantage normally attended herewith. that thus also the base resistivity of the transistor is increased and the limit frequency for the operation of the transistor is decreased,

does not occur in the present case, since the base resistivity occurring at the base electrode b may be kept low by suitable choice of the voltage source 5, while the base resistivity occurring at the electrode h, does substantially not affect the limit frequency, as stated above.

A further method to increase the resistivity between the two base electrodes b and b; is shown in FIG. 3. Herein a fourth zone 4 is provided between the zones 1 and 2 and opposite the third zone, which zone 4 is normally floating, so that the sectional area of the mass it for the :urrent flowing from the base electrode b to the base :lectrode b; is materially reduced at the area of the zone I. The zone 4 may, if desired, be in contact with the zone 3.

In order to facilitate the manufacture of the zone 3 inder certain conditions, it may be made, if desired. of wo separate, electrically interconnected zones, arranged )pposite the zones 1 and 2 respectively.

FIG. 4 shows a further embodiment in which the cur- 'ent passing through the mass n from the base electrode to the base electrode b affects only little the transistor iperation between the portions l-n-3 and 3-n-2 respecively, the three zones 1, 3 and 2 being adjacent one mother in the transistor element.

FIG. 5 shows a variant of the circuit shown in FIG. 2. n which the voltage source V is included in the circuit f the base electrode h while the emitter electrode e a connected to earth. The circuit operates in a manner imilar to that of the circuit shown in FIG. 2.

FIG. 6 shows a variant of the circuit shown in FIG. 2, 1 which the direct voltage source 5 is replaced by an lternating voltage sourve V for example, a pulsatory oltage or a square-wave voltage. As long as this voltge renders the electrode b positive relative to earth, the ortions S n-2 cannot operate as a transistor, so that inependently of the value of the voltage source V no sigal voltage is produced across the output impedance 6. lowever, when the electrode b becomes negative relative earth, the required bias voltage for a satisfactory transtor bperation of the portions ln-3 and 3 n-2 is at the me time obtained, so that a signal voltage varying with is source V is produced across the output impedance 6.

If desired, the voltage of the source V may be varied l some way or other with that of the source V An exrnple thereof is given in the amplitude detector circuit town in FIG. 7, in which part of the input voltage V is ipplied in one phase to the emitter electrode e and part i it in the opposite phase to the base electrode b Thus nly during one phase of the voltage V current flows to ie collector electrode c, so that subsequently to smoothg with the aid of a collector capacitor 10, a voltage cor- :sponding to the amplitude of the voltage V is produced :ross the output impedance 6. FIG. 8 shows a variant of the circuit shown in FIG. 7, Ir modulating two signals supplied by the sources V Id V respectively. In this case the voltages from the urce V supplied to the emitter electrode 0 and the tse electrode b; are adjusted in a manner such that no meat flows from the source V directly through the ciriit of the source V so that a reaction of the source V 1 the source V is avoided. On the other hand the curnt flowing via the collector electrode c through the outit impedance 12, selective for a mixed frequency varies ith the two sources V and V,, so that a mixed oscillation produced across this output impedance 12. In all these circuits it is important to include decoupled sistors for the signal oscillations in the emitter circuit ld/OI' one of the base circuits of the transistor, in order reduce the natural drift of the working point of the wit. As a matter of course, the earth connection in e circuits shown may be provided at a different area the arrangement.

FIG. 9 shows a further possibility of connecting a tnsistor element according to the invention, i.e. a cirit for demodulatin a freouencv-modulated si nal. For

this purpose the signal is supplied through two substantially critically coupled circuits l8 and 20; a tapping of the circuit 20 is connected via an inductor l9, coupled fixedly with the circuit 18, to the electrode c, operating as the emitter electrode, of the transistor clement, while the ends of the circuit 20 are connected to the two base electrodes b, and b; respectively. Thus a voltage difference substantially proportional to the frequency sweep of the signal across the circuit 18 is produced across the intermediate-frequency smoothing filter 22 between the electrodes e and c, operating as collector electrodes. A filter 21 included in the circuit of the emitter electrode e, having a high impedance for undesired amplitude modulations of the signal, serves to suppress this amplitude modulation.

The invention provides numerous other variants of circuits than those indicated. As a matter of course, the nand p-zones may be interchanged in the drawing, if the polarities of the voltage sources are reversed.

What is claimed is:

1. A transistor comprising a semi-conductive body of one conductivity type, at least three spaced zones within the body of a conductivity type opposite to said one conductivity type, two of said zones each being spaced from a third zone by semi-conductive material of said one type having a thickness smaller than the characteristic diffusion length of minority carriers in said One type material, said two zones being spaced from each other by semi-conductive material of said one type having a thickness greater than said characteristic diffusion length, a pair of connections secured to said body of said one type material at spaced positions, and connections secured to at least said two zones of said opposite type material.

2. A transistor as claimed in claim 1 wheren the pair of connections secured to said body are secured to opposite ends of the body each in the vicinity of one of said two zones.

3. A transistor as claimed in claim 2 wherein means are provided for increasing the electrical resistivity of the semiconductive body between said pair of connections.

4. A transistor comprising a semi-conductive body of N-type material, three spaced zones of P-type material within the body. two of said zones being smaller than said third zone and lying on one surface of said body and being spaced by N-type material, the third zone lying on the opposite surface of said body and being spaced from each of said two zones by N-type material, the spacing between each of said two zones and said third zone being less than the characteristic diffusion length of minority carriers in said N-lype material, the spacing between said two zones being greater than said characteristic diffusion length, terminal means secured to said two zones, and terminal means secured to said body at opposite ends thereof with the three zones therebetween.

5. A circuit arrangement including a transistor element comprising a scmi conductive body of one conductivity type, at least three spaced zones within the body of a conductivity type opposite to said one conductivity type, two of said zones each being spaced from said third zone by semi-conductive material of said one type having a thickness smaller than the characteristic diffusion length of minority carriers in said one type material, said two zones being spaced from each other by semiconductive material of said one type having a thickness greater than said characteristic diffusion length, a pair of terminal means secured to said body of said one type material each in the vicinity of one of said two zones, terminal means secured to said two zones of said opposite type material, a source of signals connected between a terminal of one of said two zones and the terminal to the body in the vicinity of said one zone, means coupled to the terminal of the other of said two zones for deriving an amplified signal therefrom, and a source of DC. potential connected to the other terminal tn Hm lsrvln 6. A circuit arrangement as claimed in claim wherein a source of potential is coupled to the terminal of the other of said two zones.

7. A circuit arrangement including a transistor clement comprising a semi-conductive body of one conductivity type, at least three spaced zones within the body of a conductivity type opposite to said one type, two of said zones each being spaced from said third zone by semi-conductive material of said one type having a thickness smaller than the characteristic diffusion length of minority carriers in said one type material, said two zones being spaced from each other by semi-conductive material of said one type having a thickness greater than said characteristic diffusion length, a pair of terminal means secured to said body of said one type material each in the vicinity of one of said two zones, terminal means secured to said two zones of said opposite type material, a source of signals connected between a terminal of one of said two zones and the terminal to the body in the vicinity of said one zone, means coupled to the terminal of the other of said two zones for deriving an amplified signal therefrom, and a second source of signals connected to the other terminal to the body.

8. A circuit arrangement as claimed in claim 7 wherein the second source of signals produces a square-wave signal functioning as a gating signal.

9. A circuit arrangement including a transistor element comprising a semi-conductive body of one conductivity type, at least three spaced zones within the body of a conductivity type opposite to said one conductivity type, two of said zones each being spaced from said third zone by semi-conductive material of said one type having a thickness smaller than the characteristic diffusion length of minority carriers in said one type material, said two zones being spaced from each other by semi-conductive material of said one type having a thickness greater than said characteristic diffusion length, a pair of terminal means secured to said body of said one type material each in the vicinity of one of said two zones, terminal means secured to said two zones of said opposite type material, a source of signals and means for supplying said signals in phase opposition to a terminal to one of said two zones and to the terminal to the body in the vicinity of the other of said two zones.

10. A circuit arrangement as claimed in claim 9 wherein means are coupled to the terminal of the other of said two zones for deriving an output signal therefrom.

11. A circuit arrangement including a transistor element comprising a semi-conductive body of one conductivity type, at least three spaced zones within the body of a conductivity type opposite to said one conductivity type, two of said zones each being spaced from said third zone by semi-conductive material of said one type having a thickness smaller than the characteristic diffusion length of minority carriers in said one type material, said two zones being spaced from each other by semi-conductive material of said one type having a thickness greater than said characteristic diffusion length, a pair of terminal means secured to said body of said one type material each in the vicinity of one of said two zones, terminal means secured to said three zones of said opposite type material, a source of signals, means for supplying said signal in phase opposition to said terminals secured to said body, means for coupling said signal with a phase difference varying with signal frequency to the third zone, and means coupled to said two zones for deriving an output signal therefrom.

12. A semiconductor device comprising in combination a body of semiconductor material of one carrier type having a pair of opposed surfaces, an emitter mounted on one of said surfaces to form a junction of predetermined area therewith, a pair of collectors mounted on the other of said surfaces to form junctions of predetermined area therewith, each of said collector junctions being separated from said emitter junction by a distance sufficiently small to permit an appreciable number of carriers injected across said emitter junction to reach each of said collector junctions by diffusion, at least a portion of said emitter junction being directly opposite each of said collector junctions, and means independent of said emitter and collector junctions for establishing different electrostatic potentials at different points of said body adjacent to said emitter in response to suitably applied voltages.

13. In combination, a body of semiconductonmaterial of one carriertype having a pair of opposed surfaces, an emitter mounted on one of said surfaces to form a junction of predetermined area therewith, a pair of collectors mounted on the other of said surfaces to form junctions of predetermined area therewith, each of said collector junctions being separated from said emitter junction by a distance sufficiently small to permit an appreciable number of carriers injected across said emitter junction to reach each of said collector junctions by diffusion, at least a portion of said emitter junction being directly opposite each of said collector junctions, means for making contact to said emitter, said collectors and said body, means for interconnecting the contact means including a source of voltage, a signal source, and circuit elements to cause a flow of current from said emitter to said collectors, means independent of said emitter or collector for establishing different electrostatic potentials at different points on said body adjacent to said emitter in response to suitably applied voltages for varying current flow from said emitter to said collectors.

14. In combination, a body of semiconductor material of one carrier type having a pair of opposed surfaces, an emitter mounted on one of said surfaces to form a junction of predetermined area therewith, a pair of collectors mounted on the other of said surfaces to form a junction of predetermined area therewith, each of said collectors being separated from said emitter junction by a distance sufficiently small to permit an appreciable number of carriers injected across said emitter junction to reach each of said collector junctions by diffusion, at least a portion of said emitter junction being directly opposite a respective portion of each of said collector junctions, a pair of contacts for establishing different electrostatic potentials at different points of said body adjacent to said emitter in response to suitably applied voltages, means for applying signals between said emitter and each of said contacts for producing current flow from said emitter to said collectors, and means for deriving an output current between each of said collectors and a respective contact of said pair of contacts.

15. A circuit including a semiconductor device comprising a body of semiconductor material, an input emitter electrode and a plurality of collector electrodes mounted on said body, a pair of base electrodes mounted on said body, a signal source connected between both of said base electrodes and said emitter, and another signal source connected between said base electrodes for applying an electric field along said device substantially transversely of the paths between said emitter electrode and said collector electrodes.

16. A circuit including a semiconductor device comprising a body of semiconductor material, an input emitter electrode and a pair of collector electrodes mounted on said body, a pair of base electrodes mounted on said body, a signal source connected between both of said base electrodes and said emitter electrode, and another signal source connected between said base electrodes for applying an alternating field across said body and switching the current from said emitter to one or the other of said collector electrodes.

17. A semiconductor device comprising an elongated body of semiconductor material, an emitter rectifying electrode and a pair of collector rectifying electrodes mounted on said body, a plurality of base non-rectifying electrodes mounted on said body at the ends thereof, means connected to said emitter electrode for applying a first sig- 7 nal thereto and means connected between said base electrodes for applying a second signal therebetween and establishing an electric field through said body for switching the current from said emitter to one or the other of said collector electrodes.

18. A circuit including a semiconductor device comprising an elongated body of semiconductor material of one condtlctivity type, an emitter rectifying electrode of opposite conductivity type mounted on one surface of said body and a pair of collector rectifying electrodes of opposite conductivity type mounted on the opposite surface of said body, a pair of non-rectifying base electrodes connected to said body at opposite ends thereof, a first signal source connected to said emitter electrode, and another signal source connected between said base electrodes whereby a current controlling field is applied to said body between said base electrodes.

19. A transistor comprising a semi-conductive body of P typc material, three spaced zones of N-type material within the body, two of said rones being smaller than said third zone and lying on one surface of said body and being spaced by P-type material, the third zone lying on the opposite surface of said body and being spaced from each of said two zones by P-type material, the spacing be- .ween each of said two zones and said third zone being less than the characteristic diffusion length of minority :arriers in said P-type material, the spacing between said two zones being greater than said characteristic diffusion length, terminal means secured to said two zones, and terminal means secured to said body at opposite ends thereof with the three zones therebetween.

20. A semiconductor device comprising a body of semi- :onductor material of a particular conductivity type and having two opposed surfaces; a first rectifying electrode an one of said surfaces; a plurality of second rectifying :lectrodes on the other of said surfaces, each combination of a first and a second rectifying electrode defining the ends of a charge carrier path therebctwcen; a pair of nonrectifying electrodes positioned on said body along an axis transverse to said charge carrier paths and capable of :stablishing an electric field transverse to and intersecting raid paths when a voltage is applied thereto, and means or applying voltages to the electrodes at which current s caused to flow between the rectifying electrodes on opwosed surfaces along the said charge carrier paths.

2]. A circuit arrangement comprising a transistor, said 'runsistor including a semi-conductive body portion of one "onductivity type, a first zone the opposite conductivity 'ypc adjacent the body portion forming a first p-n junc 'ion of substantial extent with the said body portion, sec- Cit our! and third spaced stir/ace zones of the opposite conductivity type located within said body portion in opposed relation to the first p-n junction and forming second and third p-n junctions with said body portion, said second and third p-n junctions being each spaced from said first 1-11 junction by a distance having a value smaller than the characteristic diffusion length of minority carriers in said one! type material, said second and third p-n jurietions being spaced from each other by a distance having a value which is greater titan said characteristic difiusion length, and means connecting said zones and said body portion such that the second zone, the first zone and the intervening body portion function as a first transistor ampli/icr, and the third zone, the first zone and the intervening body portion function as a second transistor amplifier, but as a result of their spacing direct transistor action between lill' second and third zones via the intervening hotly portion is avoided.

22. A circuit arrangement as set forth in claim 21 and further including means for biasing as a collector elecilOt/t one of the second and third zones relative to the said body portion and mcans for forward-biasing the other of the second and thin] zones relative to the said body portion.

References Cited The following references, cited by the Examiner, are of record in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,095,998 10/1937 McNary 250-21 2,100,458 11/1937 Walter 250-21 2,569,347 9/1951 Shockley 307-885 2,600,500 6/1952 Haynes et al 179-171 2,644,859 7/1953 Barton 179- 17l 2,655,610 10/1953 Ebers 307-885 2,657,360 10/1953 Wallace 250-3624 2,663,806 12/1953 Darlington 307-885 2,666,814 1/1954 Shockley 307-8815 2,742,383 4/1956 Barnes et a1 307-885 2,754.431 7/1956 Johnson 307 -88.5 2,801,347 7/[957 Dodge 307-885 DONALD D. FORRHR, Primary Examiner J. ZAZWORSKY, Assistant Examiner US. Cl. X.R. 

